U.S. patent number 4,759,982 [Application Number 06/941,023] was granted by the patent office on 1988-07-26 for transfer graphic article with rounded and sealed edges and method for making same.
This patent grant is currently assigned to Minnesota Mining and Manufacturing Company. Invention is credited to John W. Frank, Jeffrey R. Jenssen, Kenneth G. Olson.
United States Patent |
4,759,982 |
Jenssen , et al. |
July 26, 1988 |
**Please see images for:
( Certificate of Correction ) ** |
Transfer graphic article with rounded and sealed edges and method
for making same
Abstract
A process for preparing a transfer graphic article having a
protective clear coat in precise registration therewith such that
the graphic has rounded and sealed edges, and the article produced
thereby. The edges of the underlying adhesive are sealed by the
clear coat such that improved solvent resistance is achieved.
Inventors: |
Jenssen; Jeffrey R. (Woodbury,
MN), Olson; Kenneth G. (Cottage Grove, MN), Frank; John
W. (Cottage Grove, MN) |
Assignee: |
Minnesota Mining and Manufacturing
Company (St. Paul, MN)
|
Family
ID: |
25475813 |
Appl.
No.: |
06/941,023 |
Filed: |
December 12, 1986 |
Current U.S.
Class: |
428/343;
29/527.4; 428/187; 428/192; 428/194; 428/31; 428/42.1; 428/914 |
Current CPC
Class: |
B44C
1/1733 (20130101); B44C 1/1737 (20130101); B41M
7/0045 (20130101); Y10S 428/914 (20130101); Y10T
29/49986 (20150115); Y10T 428/24736 (20150115); Y10T
428/1486 (20150115); Y10T 428/28 (20150115); Y10T
428/24793 (20150115); Y10T 428/24777 (20150115) |
Current International
Class: |
B44C
1/17 (20060101); B41M 7/00 (20060101); C09U
007/02 (); B60R 013/00 (); B41M 003/12 (); B32B
023/02 () |
Field of
Search: |
;428/31,40,343,913.3,914,194,41,195,201,192 ;29/527.4 |
References Cited
[Referenced By]
U.S. Patent Documents
Primary Examiner: Lesmes; George F.
Assistant Examiner: Zirker; D. R.
Attorney, Agent or Firm: Sell; Donald M. Smith; James
Jordan; Robert H.
Claims
What is claimed is:
1. A dry transfer article for application to a substrate to provide
a design thereon, said article comprising:
(A) a graphic pattern;
(B) a layer of adhesive underlying said graphic pattern in exact
registration therewith, wherein said adhesive is capable of
providing adhesion to said graphic pattern and said substrate;
and
(C) a resinous film-formed protective clear coat in precise
registration with said graphic pattern and said layer of adhesive,
said clear coat having a rounded profile, covering said graphic
pattern, and sealing the edges of said graphic pattern and said
adhesive layer.
2. The article of claim 1 wherein said graphic pattern comprises a
film.
3. The article of claim 2 wherein said graphic pattern further
comprises a film of at least one imaging composition which covers
at least a portion of the surface of said graphic pattern.
4. The article of claim 1 wherein said protective clear coat
comprises an aliphatic polyurethane.
5. The article of claim 1 wherein said protective clear coat is
curable with ultraviolet radiation.
6. The article of claim 1 wherein said protective clear coat has
reacted with said adhesive.
7. The article of claim 6 wherein said protective clear coat
contains an isocyanate and said adhesive contains acrylic acid.
8. The article of claim 1 further comprising a release liner.
9. The article of claim 8 further comprising an application tape.
Description
FIELD OF INVENTION
This invention relates to a transfer graphic article, and to a
method for making same. More particularly, it relates to an article
comprising a transfer graphic having a protective coating
thereover, such that the graphic has rounded and sealed edges.
BACKGROUND
On site application of paint directly to a surface to be decorated
is the time-honored method for providing a graphic design, such as
a decorative design. While such a process provides many aesthetic
and physical features, including realistic appearance, color
flexibility, durability to abrasion, weathering and chemical
attack, it also suffers from many disadvantages. For example,
relatively skilled labor is necessary. Long application times are
usually the rule, and potential contamination to adjacent areas,
particularly mechanical equipment, can occur. Accordingly,
prefabricated film graphics have been utilized to avoid many of
these disadvantages. Such film graphics, often called "decal" or
"transfer graphic", when utilized on the exterior surface of
vehicles, typically require extreme resistance to abrasion and
chemical attack because of exposure of the vehicle surfaces to
various atmospheres or environments. Accordingly, such graphics
must generally be provided with a protective clear coat over the
graphic areas.
This protective clear coat can be located in registry with the
graphic area by applying a continuous layer of clear coat over the
graphic and non-graphic areas, and subsequently cutting through the
several layers precisely at the outline of the graphic area,
typically called "die cutting" or "kiss cutting". This approach
results in substantially vertical or right angle edges of the
graphic and protective clear coat which can collect dirt, wax, and
other foreign materials which can detract from the aesthetics of
the applied graphic design. Responsive thereto, a sealing agent,
e.g., SCOTCHCAL Brand 4150 Edge Sealer, available from the
Minnesota Mining and Manufacturing Company ("3M") may be applied
about the edges of such a graphic after application to the vehicle.
The sealing agent protects the exposed sides of the graphic and
adhesive from chemical attack and reduces the mechanical forces
acting thereon. This technique is most typically practiced in the
airline industry.
A second approach is to apply the protective clear coat only to
graphic areas, as, for example, by screen printing, or utilizing a
stencil with an open area corresponding precisely to the outline of
the graphic design. Those skilled in the art are aware of the
difficulty encountered with such a process, because of factors such
as dimensional changes in the film substrate, tension variables in
the screen mesh, and accurate positioning of the substrate in
registry with the stencil. Small graphics, such as those with
overall dimensions of not greater than about 12 inches.times.12
inches (30 centimeters.times.30 centimeters) can generally be
manufactured with satisfactory registration by those having
requisite skill. However, this becomes much more difficult for
larger graphic areas, and particularly for decorative items such as
pin stripes which are common for the vehicle or automotive
market.
U.S. Pat. No. 4,356,617 (Coscia) discloses the formation of a
raised dike around a graphic design for the purpose of controlling
the flow of a coating composition applied thereto. The reference
further teaches that such flow may also be controlled by a groove
or gap around the design if the coating composition has sufficient
surface tension. U.S. Pat. Nos. 4,332,074 (Auld et al.) and
4,605,575 (Auld et al.) disclose utilization of integral bezels for
similar purpose. Such techniques do not provide application of the
protective clear coat to the adhesive layer which adheres the
graphic design to a desired substrate, thereby leaving the edges of
the adhesive exposed and subject to collection of foreign materials
and environmental degradation.
Yet another approach which could be utilized is to apply the
protective clear coat with a substantial oversize border to assure
complete coverage of the graphic area. While this method achieves
the required objective of protection for the graphic design, it is
generally considered not to be aesthetic.
Application Ser. No. 846,754, filed Apr. 1, 1986, commonly assigned
herewith, discloses a graphic pattern having a protective coating
thereon in exact registration therewith and a process for forming
the same. It is taught that adhesive may be applied to the bottom
of the coated graphic for application to a substrate. According to
the process disclosed therein, an imaging composition, which has
sufficient surface tension to wet a carrier, is applied, e.g., by
screen-printing, to the carrier and dried to form a graphic pattern
thereon. A liquid protective coating is applied over the graphic
pattern in an oversize border therewith. The protective coating has
sufficient surface tension to wet the graphic pattern but not the
carrier surface whereby during drying the protective coating will
dewet the major surface of the carrier to provide exact
registration with the graphic pattern. Following drying of the
protective coating, the article is laminated to a premask tape, the
carrier is removed and an adhesive is applied to the underside of
the graphic pattern for subsequent transfer to a substrate.
Although detailed transfer graphics may be achieved by such method,
the adhesive is not covered by the protective coating, thus
resulting in exposed edges subject to collection of foreign
materials and environmental attack.
Although application of a protective clear coat by screen printing
is a typical technique, other methods such as roller coating or
spray coating may also be considered, providing a dry film
thickness of from about 0.5 to about 4 mils (0.01 to 0.1
millimeters) thickness is achieved.
Summarizing, an acceptable protective clear coat should be of
sufficient thickness to provide adequate wearability and resistance
to chemical environments, and precisely cover the graphic area,
whether same be large or small, and whether it be a simple
geometric shape, such as a narrow width line, or a complex
intricate design. An acceptable protective clear coat should
further cover the adhesive means which secures the graphic to the
substrate thereby inhibiting unsightly collection of foreign matter
and protecting the adhesive. Known techniques described above do
not satisfy all these requirements.
Accordingly, the present invention provides precise registration of
a clear protective coat over a graphic pattern and underlying
adhesive; the protective coat has tapered, rounded and sloping
edges which seal the edges of the graphic pattern and adhesive,
thereby inhibiting the buildup of wax and foreign matter at the
edge portions, and looks integrated with the substrate; i.e.,
provides a paint-like look; the process can accommodate varying
process tolerances, operator variability and equipment tolerances;
and the process provides a lenticular appearance on thin pin
stripes, such as may be placed on vehicle surfaces.
SUMMARY OF INVENTION
In accordance with the invention, a dry transfer graphic article
comprising a graphic pattern and underlying adhesive is provided
which has a protective coating thereon in "precise registration"
(as defined herein) therewith such that the graphic has rounded and
sealed edges and a paint-like appearance when applied to a desired
substrate. The protective clear coat protects the transfer graphic
from abrasive forces and prevents collection of foreign matter at
the edges of the graphic pattern and underlying adhesive. Further,
the clear coat provides unexpected solvent resistance to the
adhesive, thereby improving the durability and longevity of such
graphics. There is also provided a process for making such a
graphic transfer article.
"Precise registration" is defined herein to mean a slight oversize
border which is approximately 5 mils (0.12 millimeters) or less in
width. Such borders provide the desired protection and sealing of
the graphic pattern and adhesive, but are essentially
undistinguishable to the unaided eye, thus clear coats having such
borders appear to be in precise registration with the graphic or
visually coincident therewith.
In brief summary, the dry transfer article provided herein
comprises: (1) a graphic pattern; (2) an underlying layer of
adhesive in exact registration therewith; and (3) a clear coat
having a rounded profile which covers the graphic pattern and seals
the edges thereof and edges of the underlying adhesive layer.
Briefly summarizing, the process for making such a transfer graphic
article comprises: (1) providing a carrier having a major surface;
(2) coating a layer of adhesive, typically pressure-sensitive
adhesive, thereon; (3) applying an imaging stratum, e.g., a polymer
film of desired color, thereover; (4) trimming the imaging stratum
and underlying adhesive in imagewise fashion to provide the desired
graphic pattern, e.g., by kiss-cutting and removal of the
nonimagewise portions of the same; (5) applying a liquid protective
coating over the graphic pattern, in substantial registration
therewith, the protective coating composition having a surface
tension sufficient to wet the graphic pattern and exposed edges of
the underlying adhesive, but not the major surface of the carrier;
and (6) drying the coating of protective material, whereby upon
drying the protective clear coat dewets or retracts from the major
surface of the carrier into precise registration with the graphic
pattern, sealing the edges of the graphic pattern and underlying
adhesive and providing a rounded profile. If desired, an imaging
composition, e.g., ink, may be applied to the imaging stratum
before trimming to provide special effects, e.g., a multicolor
graphic, etc.
BRIEF DESCRIPTION OF DRAWING
The invention is further explained with reference to the drawing
wherein:
FIG. 1 is a cross-sectional representation of an imaging stratum
and underlying adhesive layer which have been applied to a
carrier;
FIG. 2 is a cross-sectional representation of the construction of
FIG. 1 after an image composition has been printed thereon and a
desired graphic pattern has been formed by kiss-cutting and weeding
in an imagewise fashion;
FIG. 3 is a cross-sectional representation of the construction of
FIG. 2 after a liquid protective coating has been applied and dried
thereon;
FIG. 4 is a cross-sectional representation of the construction of
FIG. 3 after lamination of an application tape thereto; and
FIG. 5 is a cross-sectional representation of a transfer graphic of
the invention being applied to a substrate.
These figures, which are not to scale, are intended to be merely
illustrative and not limiting.
DETAILED DESCRIPTION OF INVENTION
The invention relates to a transfer graphic article having a
protective coating thereon such that the article, including graphic
pattern and underlying adhesive in registry therewith has rounded
and sealed edges. The protective coating is in precise registration
with the graphic pattern thereby providing an aesthetically
pleasing unitary appearance. The invention also relates to a
process for the manufacture of a dry transfer graphic article which
comprises the steps of applying to a carrier surface an imaging
stratum and underlying adhesive to form a desired graphic pattern,
and applying thereover a protective clear coat, the clear coat
being applied beyond the edge definition of the image areas, the
surface energy of the carrier being sufficiently low relative to
the surface tension of the protective clear coating that
non-wetting of the carrier by the protective coating occurs, and
same therefor "creeps" back to the surface and edges of the graphic
pattern and underlying adhesive into precise registration with the
graphic pattern and underlying adhesive.
The carrier comprises a material which inherently has a low surface
energy, or has a low surface energy coating thereon, e.g., a paper
or polyester film with silicone coating thereon. The carrier
functions to provide a base surface having sufficient rigidity on
which to coat the adhesive and apply the imaging stratum, e.g., a
polymer film, and trim the same in imagewise fashion, e.g., by kiss
cutting and removing weed; yet has a sufficiently low comparative
surface energy such that as the clear liquid protective top coat
dries thereon, same will not wet, or will retract from, the carrier
surface onto the graphic film and and underlying adhesive. In
addition, the carrier functions as a release liner and must allow
for easy release of the graphic transfer therefrom, i.e., the
adhesion of the adhesive thereto should be releasable.
The imaging stratum comprises a material such as a polymer film.
The film is preferably a material of desired color which has a
surface energy which is higher than that of the carrier such that
when the protective clear coat is applied it will dewet or retract
from the carrier surface onto the imaging stratum and underlying
adhesive.
The underlying adhesive should provide high adhesion to the imaging
stratum and desired substrate to which the ultimate graphic is
applied, yet should releasably adhere to the carrier.
The adhesive may first be coated on the carrier and the imaging
stratum then applied thereto, or it may first be coated on the
imaging stratum, e.g., a film, following which the precoated
imaging stratum is applied to the carrier. The adhesive should form
a substantially continuous layer covering at least the area of the
desired graphic pattern, and preferably extends at least slightly
therebeyond, such that a layer of adhesive will underly
substantially all of the graphic pattern, providing secure adhesion
to the substrate. Examples of suitable adhesive-precoated films
include SCOTCHCAL Brand 3650 Series Polyvinvl Chloride Films, and
SCOTCHCAL Brand 5690 Series Polyester Films, which have acrylic
type pressure-sensitive adhesives on the back side and are
available from the Minnesota Mining and Manufacturing Company
("3M").
FIG. 1 shows carrier 10 comprising a polymer film 12 with surface
14 having a low surface energy to which adhesive 16 and imaging
stratum 18 have been applied.
If desired, e.g., for multi-color graphic patterns, an imaging
composition or material may be coated or printed on the imaging
stratum in desired pattern.
The imaging material can be comprised of conventional imaging
materials used to form graphic images on substrates, such as inks,
for example. The exact composition of the imaging material depends
on the end use properties required. The imaging material is
typically applied from a wet composition having surface tension
properties such that the composition will wet out and flow on the
imaging stratum to form a film and provide a visible printed
pattern thereon. Imaging materials may be colored or colorless,
although colored compositions are preferred. If desired, special
effects may be achieved if the composition provides a product which
is visible under ultraviolet light, but is colorless under ordinary
ambient light. Conventional inks can be utilized, such as the vinyl
or vinyl acrylic inks commerically available.
Screen printable inks can be classified on the basis of formation
of an ink film, and the vehicles used for that film formation. For
example, solvent-based inks form a film by evaporation of the
various solvents contained therein, i.e., the wet film is dried.
Curable inks provide a film which becomes polymerized through
chemical change. Examples of inks include enamels; solvent-based
inks, e.g., those containing lacquers and other solvents, poster
inks, and water-based inks; those containing 100 percent solids,
such as those based on epoxies, ultraviolet exposure systems,
plastisols, etc.; and specialty inks, such as those which are
expandable, those which exhibit electrical properties, etc.
To obtain good wetting, i.e., maximum surface contact on the
imaging stratum, the surface tension of the ink must be equal to or
less than the critical surface tension of the imaging stratum. In
other words, the imaging stratum must have a higher degree of
surface wetability than the imaging composition. However, the
surface tension of the film formed by the imaging composition must
be greater than that of the carrier surface such that the
protective coating will properly dewet from the carrier surface to
achieve desired registration with the graphic. If the surface
tension of the film formed by the imaging composition is not
sufficiently greater than that of the carrier surface, precise
registration of the clear coat with the graphic pattern may not be
achieved. Specific solvents, surfactants, and other conventional
and known additives can be utilized to modify the surface
properties of the imaging composition, as desired.
Multiple imaging composition films, such as of different colors,
may also be printed in sequence if desired.
The imaging stratum, imaging composition film, if any, and
underlying adhesive are then trimmed in an imagewise fashion to
provide the desired graphic pattern, such as by kiss cutting in
imagewise fashion and removing undesired portions, i.e., weed. Care
should be taken when kiss cutting in that cutting too deeply, i.e.,
into the carrier, may tend to cause the clear coat composition to
incompletely dewet from the carrier during drying, whereas failure
to cut deeply enough, i.e., not completely through the adhesive
layer, may interfere with complete stripping of the weed. FIG. 2
shows adhesive 16, imaging stratum 18, and imaging composition film
20 on carrier 10 after kiss-cutting and weeding to form the desired
graphic pattern.
This invention relates to a process utilizing the surface tension
characteristics of each of the four components of the process,
i.e., the carrier surface, the imaging stratum, the imaging
composition, if any, and the protective clear coat. Usually, one
begins with a determination of the critical solid surface tension
of the carrier surface and then tailors the other components to
meet the requisite surface tension requirements. The surface energy
of a film can be determined in a number of ways. For example, a
series of liquids of known surface tension can be applied to a
smooth test surface. The contact angle of these liquids on the
solid surface is measured, and this information can then be plotted
against the known surface tension of the respective liquids.
Extrapolation of such data to a zero contact angle provides the
solid surface tension, i.e., that of the carrier surface, since at
this point the surface tension of the solid film is approximately
equal to that of the liquid. This surface tension thus becomes the
critical solid surface tension. When utilizing this procedure with
a silicone-coated carrier, surface tension was calculated to be
23.8 dynes/centimeter, which is in agreement with the reported
literature value of 24 dynes/centimeter.
Similarly, results of contact angle measurements for liquids having
known values of liquid surface tension due to dispersion forces and
polar forces, both of which contribute to surface free energy can
be utilized.
Finally, wetting tension test kits are commercially available to
determine the critical surface tension of specific film
substrates.
Examples of typical surface tension values include about 32
dynes/centimeter for polyvinyl chloride films which can typically
be corona treated to yield values of about 60 to 70
dynes/centimeter, and about 26 to 35 dynes/centimeter for typical
vinyl inks which can also be corona treated to yield surface
energies of greater than 60 dynes/centimeter.
Once the critical solid surface energy of the carrier surface is
known, an imaging stratum can be selected and an imaging
composition can be tailored thereto to provide or produce a good
graphic pattern which can be clear coated with the desired precise
or visually coincident registration.
Once the desired graphic pattern is appropriately formed on the
carrier surface, the protective clear coat can be formulated based
on solvent selection, particular resin, and other additives which
together provide a formulation which is capable of wetting the dry
graphic pattern and exposed adhesive layer sufficiently, and yet is
not capable of wetting the carrier surface.
Other critical factors include the solvation of the coating
composition and its rate of drying, in addition to its relative
surface tension.
The protective clear coat is made typically of a resinous
film-forming material, an example thereof being aliphatic
polyurethanes, which are conventionally utilized today to provide a
protective top coat for a transfer graphic image.
The liquid top coat is printed, as by screen printing, for example,
over the graphic pattern, and slightly beyond the edge definition
thereof, i.e., typically with an overprint margin up to about 100
mils (2.54 millimeters) wide, so as to assure complete coverage of
the graphic pattern. As this liquid coat dries, it will dewet,
i.e., creep or retract from the carrier where it has been
overprinted onto the graphic pattern into precise registration
therewith, and can be cured in conventional fashion. Preferably,
the liquid is printed at least 5 mils (0.12 millimeter) beyond the
edge of the graphic pattern to ensure complete sealing of the edges
of same and underlying adhesive. Overprint margins of increasing
width may cause the overcoat to puddle on the carrier or to bridge
gaps within the graphic pattern, e.g., spaces between parallel
strips such as are provided for "racing" stripes used for
automotive decoration.
Accordingly, the protective clear coat provides a variable high
thickness over the surface of the graphic pattern and seals the
edges of the graphic pattern and underlying adhesive. Thus the
clear coat protects the graphic pattern and underlying adhesive
from chemical and environmental attack, thereby increasing the
durability thereof, and also provides a unitary, paint-like
appearance, thereby improving the attractiveness thereof.
Preferably the final thickness of the clear coat is at least 0.5
mil (0.01 millimeter), and not greater than about 4 mils (0.1
millimeter). Thinner clear coats tend to provide less effective
protection to the graphic pattern and underlying adhesive whereas
those substantially thicker than the indicated range may tend to
give the graphic an undesirable artificial appearance.
FIG. 3 shows the rounded profile provided by clear coat 22 after it
has dried. The edges 24 of imaging stratum 18, underlying adhesive
16, and imaging composition film 20 have been sealed by clear coat
22.
Surprisingly, in addition to preventing collection of foreign
matter at the edges of the transfer article, it has been found that
the clear coat provides excellent solvent resistence to the
graphic, particularly to the underlying adhesive. Thus it is
preferred that the clear coat and underlying adhesive are mutually
reactive to achieve an optimum seal. For instance, an
isocyanate-containing clear coat composition and acrylic
acid-containing adhesive will typically react to provide a chemical
bond between the adhesive layer and clear coat, such a bond
typically providing exceptional solvent resistance to the adhesive
layer.
As shown in FIG. 4, the article can then be laminated to a
conventional application tape 26, i.e., a flexible film 28 having a
low-tack adhesive 30 thereon, whereupon imaging composition film
20, imaging stratum 18, underlying adhesive 16, and overlying
protective coat 22 can be stripped away from the carrier 10, which
can then be discarded, and the transfer article then applied to a
substrate. Following burnishing action, e.g., with a squeegee, the
application tape is removed leaving the transfer article adhered to
the substrate. FIG. 5 shows the transfer article adhered to
substrate 32 after application tape 26 has been partially
removed.
In this manner, there is provided a low profile, high performance,
durable graphic transfer system, having special utility in the
automotive market place. For example, the invention can provide an
automotive stripe or marking which is unique in appearance and
performance properties, in that the graphics produced by the
invention have rounded edges and closely similate paint, a
technique not heretofor available with a transfer graphic system.
Further, the graphics disclosed herein are very durable and
resistant to forces typically encountered by automobile finishes,
e.g., abrasive action, dirt impact, and solvent attack.
The invention will now be further illustrated by the following
illustrative examples, wherein all parts are by weight unless
otherwise specified.
EXAMPLE 1
A SCOTCHCAL Brand 3655 Film comprising a polyvinyl chloride film
coated with an acrylic pressure-sensitive adhesive protected with a
silicone coated paper release liner was used as the imaging
stratum, underlying adhesive and carrier.
The film and underlying adhesive were hot kiss cut in an imagewise
fashion ("racing" stripes) using a Teflon-coated, etched magnesium
die at a temperature of 350.degree. F. (175.degree. C.) to produce
edges with a tapered profile.
The weed was then removed from the carrier to produce the graphic
pattern.
A clear coat was then applied to the graphic pattern with an
overprint margin of about 20 to 40 mils (0.50 to 1.0 millimeter)
using a 110 mesh screen. The clear coat, a two component
polyurethane, had the following formulation:
______________________________________ Component Parts
______________________________________ DESMOPHEN 651A-65 - rigid
polyester polyol; 46.5 65% solids in ethyl glycol acetate;
equivalent wt. of 325; % hydroxyl of 5.2 (available from Mobay
Chemical, Inc.) DESMOPHEN 670-90 - flexible polyester polyol; 12.5
viscous liquid, 90% solids; equivalent wt. of 439; % hydroxyl of
3.9 (available from Mobay Chemical, Inc.) DESMDUR N-100 - aliphatic
polyisocyanate; 31.0 viscous liquid, 100% solids; equivalent wt. of
190; % NCO of 22 (available from Mobay Chemical, Inc.) TINUVIN 770
- hindered amine stabilizer 0.9 (available from Ciba-Geigy, Inc.)
TINUVIN 328 - benzotriazole UV absorber 3.0 (available from
Ciba-Geigy, Inc.) MULTIFLOW - acrylic copolymer resin solution, 1.8
50% solids in xylene; specific gravity 25/25.degree. C. of
0.925-0.940; refractive index at 25.degree. C. of 1.481-1.485
(available from Monsanto Industrial Chemicals Co.) FC-430 -
fluorocarbon flow additive 1.0 (available from 3M) CARBITOL ACETATE
- diethylene glycol monoethyl 5.1 ether acetate (available from
Union Carbide) ______________________________________
The clear coat was cured at 165.degree. F. (75.degree. C.) for one
hour.
An application tape was laminated to the transfer graphic
article.
The graphic was applied to a painted steel plate substrate.
The transfer graphic had rounded, unitary appearance similar to
that of paint.
The solvent resistance of the graphic was tested by soaking the
graphic and substrate in a solution comprising 90 parts unleaded
gasoline and 10 parts ethanol for about 40 minutes at room
temperature. After being removed, the dried transfer graphic
retained its initial, paint-like appearance, having suffered no
apparent degradation.
EXAMPLE 2
A transfer graphic was made and applied to a substrate as in
Example 1.
Solvent resistance was tested by soaking the graphic and substrate
in toluene for about 5 minutes at room temperature. After being
removed and dried, the transfer graphic retained its initial,
paint-like appearance, having suffered no apparent degradation.
EXAMPLE 3
A transfer graphic article was made as in Example 1, except the
clear coat was a lacquer acrylic based material having the
following formulation:
______________________________________ Component Parts
______________________________________ CELLOSOLVE ACETATE -
ethylene glycol mono- 40.3 ethyl ether acetate (available from
Union Carbide) CARBITOL ACETATE - diethylene glycol mono- 24.4
ethylene ether acetate (available from Union Carbide) ACRYLOID A-21
- methyl methacrylate solid 18.6 resin (available from Rohm and
Haas) Butanol 3.7 SANITIZER 160 - butyl benzyl phthalate 5.6
(available from Monsanto) 1/2 Sec-CAB - cellulose acetate butyrate
7.4 resin (available from Eastman Chemical)
______________________________________
After application to a painted steel substrate, the transfer
graphic also had a rounded, unitary appearance similar to that of
paint.
EXAMPLE 4
A transfer graphic article was made as in Example 1, except the
clear coat was an ultraviolet curable material having the following
formulation:
______________________________________ Component Parts
______________________________________ XP-173-09 - aliphatic
urethane acrylate 64.3 oligomer diluted with 25 weight percent
2-ethylhexylacrylate (available from Cargill, Inc.) Tetraethylene
Glycol Diacrylate 21.7 n-Vinyl-2-Pyrrolidone 10.0 MULTIFLOW 2.0
.alpha.,.alpha.'-diethoxyacetophenone (available from 2.0 Upjohn
Chemical, Co.) ______________________________________
The clear coat was applied to the graphic pattern with an overprint
margin of about 5 to 125 mils (0.12 to 3.18 millimeters) using a
110 mesh screen.
The clear coat was cured by actinic radiation in a Linde PS-121
Photocure chamber at a beltspeed of 30 feet (9.1 meters) per minute
in a nitrogen atmosphere.
After application to a painted steel substrate, the transfer
graphic also had a rounded, unitary appearance similar to that of
paint.
EXAMPLE 5
A transfer graphic article was made as in Example 1, except an ink
was screen printed onto the imaging stratum prior to kiss-cutting.
The ink was SCOTCHCAL Brand 3905 Ink, a polyvinyl chloride/vinyl
acetate copolymer-based ink pigmented with carbon black. The ink
was screen printed with a 230 mesh screen and cured at 190.degree.
F. (90.degree. C.) for 3 minutes.
After cooling to room temperature, a clear coat was applied thereto
as in Example 1.
Following application to a painted steel substrate as in Example 1,
the transfer graphic had a rounded, unitary appearance similar to
two parallel stripes of paint, e.g., "racing" stripes.
COMPARATIVE EXAMPLE A
A polyester film was coated with the following silicone
composition:
______________________________________ Component Parts
______________________________________ SS-4191 (a 30 wt. % solution
15.0 of dimethyl polysiloxane in toluene) Toluene 83.0 SS-4259C (an
accelerator) 1.0 SS-4192C (a silicone catalyst) 1.0
______________________________________
(The foregoing all being commercially available from the General
Electric Company).
An ink composition was then screen printed on the silicone-coated
polyester with a 110 mesh screen, the composition of the ink
being:
______________________________________ Component Parts
______________________________________ "VYHH" resin (an 87 wt. %
polyvinyl 22.0 chloride/13 wt. % polyvinyl acetate copolymer,
available from Union Carbide) RAVEN 1200 (a carbon black pigment
7.8 available from City Surface, Inc.) Dioctyl phthalate 4.3
SF-96-1000 - silicone flow agent 0.3 available from General
Electric Co.) FC431 (a fluorocarbon flow agent) 0.5 Cyclohexanone
31.2 Isophorone 31.2 Xylene 2.7
______________________________________
diluted with diisoamyl ketone to provide a viscosity of 1300 cps
(using a Brookfield viscometer No. 3 spindle). After printing, the
solvents were evaporated by heating in an air convection oven at
165.degree. F. (75.degree. C.).
A protective clear coat having the same formulation as that used in
Example 1 was diluted with CARBITOL ACETATE to a viscosity of 500
cps (using a Brookfield viscometer, No. 3 spindle).
This formulation was then screen printed over the previously
prepared ink image with an overprint margin of about 20 mils (0.50
millimeter).
The construction was then baked for two hours at about 165.degree.
F. (75.degree. C.). During drying, the coating composition dewetted
back to the edges of the ink image, thus providing excellent
registration with the underlying ink areas.
An application tape, 25-508-LC, available from Laminated and Coated
Products, Inc., comprising a 2.5 mil (0.06 millimeter) polyethylene
backing coated with a low-tack, water-based acrylic
pressure-sensitive adhesive, was laminated to the polyester film
over the coated graphic pattern. The polyester film was removed,
transferring the graphic pattern from the polyester film to the
application tape.
The underside of the graphic pattern and exposed portions of the
low-tack adhesive on the application tape were corona treated using
500 Watts at a speed of 20 feet (6.1 meters) per minute.
An adhesive formulation, comprising 19.6 weight percent adhesive
polymer (isooctyl acrylate/vinyl acetate/acrylic acid in a 74/22/4
weight ratio) and 80.4 weight percent ethyl acetate, was prepared
by mixing the ingredients together at room temperature; coating the
solution onto a silicone-coated, white polyethylene film,
05-4-HiD-ST6A/ST3A-White available from Schoeller Release Products,
Inc., to a wet thickness of about 3 mils (0.8 millimeter); and
evaporating the solvent by heating for five minutes at 165.degree.
F. (75.degree. C.). The adhesive-coated side of this film was
laminated to the corona-treated side of the application tape and
graphic pattern.
The silicone-coated polyethylene film was removed and the article
placed on a painted steel substrate such that adhesive was in
contact with the painted steel. Moderate pressure was applied to
the application tape by stroking that surface with the edge of a
polyethylene squeegee over the film structure. The application tape
was then peeled from the substrate. The graphic design remained on
the painted steel substrate and any adhesive not in registration
with the graphic article remained on the application tape.
The solvent resistance of the article was then tested by immersion
in a gasoline/ethanol mixture as in Example 1. After removal and
drying, the graphic article was inspected to reveal disfiguring
solvent attack along the edges thereof. The ink image had become
rippled and rough along the edges thereof and the underlying
adhesive in such areas had been leached out.
COMPARATIVE EXAMPLE B
A continuous layer of the protective clear coat composition
described in Example 1 was applied to SCOTCHCAL Brand 3655 Film by
screen printing the composition through a 110 mesh screen. The
clear coat was cured at 165.degree. F. (75.degree. C.) for one
hour.
The clear coat, film, and underlying adhesive were hot kiss-cut in
an imagewise fashion ("racing" stripes) using a Teflon-coated,
etched magnesium die at a temperature of 350.degree. F.
(175.degree. C.) to produce edges with a tapered profile.
The weed was then removed from the carrier to produce a graphic
article.
An application tape was laminated to the graphic article, and the
article was applied to a painted steel substrate as in Example
1.
The solvent resistance of the graphic was then tested by immersion
in a gasoline/ethanol mixture as in Example 1 and Comparative
Example A. After removal and drying, the graphic was inspected
whereupon it was observed that the adhesive had oozed from
underneath the graphic pattern.
Comparison of the results of Examples 1 and 2 with those of
Comparative Examples A and B illustrates the solvent resistance
achieved by a transfer graphic of the invention wherein the
protective clear coat seals both the graphic pattern and underlying
adhesive and the improved solvent resistance attained as compared
to that of transfer graphics wherein the clear coat is applied only
to the graphic pattern and not to the exposed edges of the
underlying adhesive.
Various modifications and alterations of this invention will become
apparent to those skilled in the art without departing from the
scope and spirit of this invention.
* * * * *